Ankara, Feb 20 (IANS): Turkish President Recep Tayyip Erdogan has said that an operation in the Syrian province of Idlib was imminent in what he said was a "final warning" to the regime in Damascus, which is currently engaged in a Russian-backed operation to take control of one of the last rebel outposts.

Erdogan's speech to members of his hardline AKP party on Wednesday came after Russia-Turkey talks on Idlib fell short of a concrete conclusion on Tuesday, reports Efe news.

"Now we are giving our last warnings. The operation in Idlib is only a matter of time," he told his political allies.

Turkey has insisted that Assad's forces stay outside the so-called de-escalation zone, an area earmarked for a cessation of violence under the auspices of Ankara and Moscow

However, in recent weeks, Assad's troops have been pushing into Idlib and the western Aleppo countryside from the south, prompting tens of thousands of civilians to flee their homes.

"We will end the aggression of the (Assad's) regime," Erdogan said on Wednesday, adding: "We will not leave Idlib to the regime and those who support it."

He added that he had discussed the topic on Wednesday with US President Donald Trump.

Turkey's defence minister, Hulusi Akar, had previously warned that Turkey was not ready to give up its observation posts in Idlib province.

In response to Erdogan's remarks, Kremlin spokesman Dmitri Peskov said a Turkish invasion of the province, the majority of which is controlled by groups opposed to President Bashar Al Assad, would be the "worst scenario".

"We are not considering the worst scenarios right now. This would not be the best possible scenario."

The Carter Centre, which has undertaken the conflict tracking project Mapping Syria, said Syrian Army troops and allies have captured roughly half of the de-escalation zone.

Save the Children and UNICEF said that around 500,000 children had been forced to flee their homes since December to escape an offensive launched by Russian-backed Syrian regime forces.

Turkey has launched several military incursions in the north of Syria. It trains Syrian militias to spearhead ground operations.

Russia's aerial support is often credited with turning Assad's fortunes around.